一.准备工作

1.准备一个redis，删除目录下的，dump.rdb文件，并修改他的配置文件：redis.windows.conf

1.修改端口：我设置为 port 70012.放开配置： cluster-enabled yes cluster-config-file nodes-7001.conf //名称可自改 cluster-node-timeout 15000

将这个redis复制5份，并修改相应配置，将端口设置为：7001,7002,7003,7004,7005,7006

2.配置Ruby环境、Redis的Ruby驱动redis.gem以及创建Redis集群的工具redis-trib.rb。

（1）下载Redis安装文件：http://download.redis.io/releases/，我们下载zip格式Redis-x64-3.2.1版本。

（2）下载Ruby安装文件：http://dl.bintray.com/oneclick/rubyinstaller/rubyinstaller-2.2.4-x64.exe

（3）下载Ruby环境下Redis的驱动：https://rubygems.org/gems/redis/versions/3.2.2，考虑到兼容性，这里下载的是3.2.2版本。

下载：https://rubygems.org/downloads/redis-3.2.2.gem

（4）下载Redis官方提供的创建Redis集群的ruby脚本文件redis-trib.rb；（我自己下载的，在文章最后，自用）

3.将所有redis文件和redis-trib.rb放在一个redis目录下：

二.启动redis群

1.在redis-trib.rb目录下输入:后面会出现选项，选yes即可；

redis-trib.rb create --replicas 0 127.0.0.1:7001 127.0.0.1:7002 127.0.0.1:7003 127.0.0.1:7004 127.0.0.1:7005 127.0.0.1:7006

三.出现问题

1.缺少redis库:

解决方法：gem install redis （安装redis库）

2.插槽15被占用，解决方法：打开每一个服务器，执行flushall、flushdb、cluster reset指令：到每个redis目录下修改：

四.资源

redis-trib.rb：将他复制到文本上并修改文本名称即可：

#!/usr/bin/env ruby # TODO (temporary here, we'll move this into the Github issues once# redis-trib initial implementation is completed).## - Make sure that if the rehashing fails in the middle redis-trib will try# to recover.# - When redis-trib performs a cluster check, if it detects a slot move in# progress it should prompt the user to continue the move from where it# stopped.# - Gracefully handle Ctrl+C in move_slot to prompt the user if really stop# while rehashing, and performing the best cleanup possible if the user# forces the quit.# - When doing "fix" set a global Fix to true, and prompt the user to# fix the problem if automatically fixable every time there is something# to fix. For instance:# 1) If there is a node that pretend to receive a slot, or to migrate a# slot, but has no entries in that slot, fix it.# 2) If there is a node having keys in slots that are not owned by it# fix this condition moving the entries in the same node.# 3) Perform more possibly slow tests about the state of the cluster.# 4) When aborted slot migration is detected, fix it. require 'rubygems'require 'redis' ClusterHashSlots = 16384MigrateDefaultTimeout = 60000MigrateDefaultPipeline = 10RebalanceDefaultThreshold = 2 $verbose = false def xputs(s) case s[0..2] when ">>>" color="29;1" when "[ER" color="31;1" when "[WA" color="31;1" when "[OK" color="32" when "[FA","***" color="33" else color=nil end color = nil if ENV['TERM'] != "xterm" print "\033[#{color}m" if color print s print "\033[0m" if color print "\n"end class ClusterNode def initialize(addr) s = addr.split(":") if s.length < 2 puts "Invalid IP or Port (given as #{addr}) - use IP:Port format" exit 1 end port = s.pop # removes port from split array ip = s.join(":") # if s.length > 1 here, it's IPv6, so restore address @r = nil @info = {} @info[:host] = ip @info[:port] = port @info[:slots] = {} @info[:migrating] = {} @info[:importing] = {} @info[:replicate] = false @dirty = false # True if we need to flush slots info into node. @friends = [] end def friends @friends end def slots @info[:slots] end def has_flag?(flag) @info[:flags].index(flag) end def to_s "#{@info[:host]}:#{@info[:port]}" end def connect(o={}) return if @r print "Connecting to node #{self}: " if $verbose STDOUT.flush begin @r = Redis.new(:host => @info[:host], :port => @info[:port], :timeout => 60) @r.ping rescue xputs "[ERR] Sorry, can't connect to node #{self}" exit 1 if o[:abort] @r = nil end xputs "OK" if $verbose end def assert_cluster info = @r.info if !info["cluster_enabled"] || info["cluster_enabled"].to_i == 0 xputs "[ERR] Node #{self} is not configured as a cluster node." exit 1 end end def assert_empty if !(@r.cluster("info").split("\r\n").index("cluster_known_nodes:1")) || (@r.info['db0']) xputs "[ERR] Node #{self} is not empty. Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0." exit 1 end end def load_info(o={}) self.connect nodes = @r.cluster("nodes").split("\n") nodes.each{|n| # name addr flags role ping_sent ping_recv link_status slots split = n.split name,addr,flags,master_id,ping_sent,ping_recv,config_epoch,link_status = split[0..6] slots = split[8..-1] info = { :name => name, :addr => addr, :flags => flags.split(","), :replicate => master_id, :ping_sent => ping_sent.to_i, :ping_recv => ping_recv.to_i, :link_status => link_status } info[:replicate] = false if master_id == "-" if info[:flags].index("myself") @info = @info.merge(info) @info[:slots] = {} slots.each{|s| if s[0..0] == '[' if s.index("->-") # Migrating slot,dst = s[1..-1].split("->-") @info[:migrating][slot.to_i] = dst elsif s.index("-<-") # Importing slot,src = s[1..-1].split("-<-") @info[:importing][slot.to_i] = src end elsif s.index("-") start,stop = s.split("-") self.add_slots((start.to_i)..(stop.to_i)) else self.add_slots((s.to_i)..(s.to_i)) end } if slots @dirty = false @r.cluster("info").split("\n").each{|e| k,v=e.split(":") k = k.to_sym v.chop! if k != :cluster_state @info[k] = v.to_i else @info[k] = v end } elsif o[:getfriends] @friends << info end } end def add_slots(slots) slots.each{|s| @info[:slots][s] = :new } @dirty = true end def set_as_replica(node_id) @info[:replicate] = node_id @dirty = true end def flush_node_config return if !@dirty if @info[:replicate] begin @r.cluster("replicate",@info[:replicate]) rescue # If the cluster did not already joined it is possible that # the slave does not know the master node yet. So on errors # we return ASAP leaving the dirty flag set, to flush the # config later. return end else new = [] @info[:slots].each{|s,val| if val == :new new << s @info[:slots][s] = true end } @r.cluster("addslots",*new) end @dirty = false end def info_string # We want to display the hash slots assigned to this node # as ranges, like in: "1-5,8-9,20-25,30" # # Note: this could be easily written without side effects, # we use 'slots' just to split the computation into steps. # First step: we want an increasing array of integers # for instance: [1,2,3,4,5,8,9,20,21,22,23,24,25,30] slots = @info[:slots].keys.sort # As we want to aggregate adjacent slots we convert all the # slot integers into ranges (with just one element) # So we have something like [1..1,2..2, ... and so forth. slots.map!{|x| x..x} # Finally we group ranges with adjacent elements. slots = slots.reduce([]) {|a,b| if !a.empty? && b.first == (a[-1].last)+1 a[0..-2] + [(a[-1].first)..(b.last)] else a + [b] end } # Now our task is easy, we just convert ranges with just one # element into a number, and a real range into a start-end format. # Finally we join the array using the comma as separator. slots = slots.map{|x| x.count == 1 ? x.first.to_s : "#{x.first}-#{x.last}" }.join(",") role = self.has_flag?("master") ? "M" : "S" if self.info[:replicate] and @dirty is = "S: #{self.info[:name]} #{self.to_s}" else is = "#{role}: #{self.info[:name]} #{self.to_s}\n"+ " slots:#{slots} (#{self.slots.length} slots) "+ "#{(self.info[:flags]-["myself"]).join(",")}" end if self.info[:replicate] is += "\n replicates #{info[:replicate]}" elsif self.has_flag?("master") && self.info[:replicas] is += "\n #{info[:replicas].length} additional replica(s)" end is end # Return a single string representing nodes and associated slots. # TODO: remove slaves from config when slaves will be handled # by Redis Cluster. def get_config_signature config = [] @r.cluster("nodes").each_line{|l| s = l.split slots = s[8..-1].select {|x| x[0..0] != "["} next if slots.length == 0 config << s[0]+":"+(slots.sort.join(",")) } config.sort.join("|") end def info @info end def is_dirty? @dirty end def r @r endend class RedisTrib def initialize @nodes = [] @fix = false @errors = [] @timeout = MigrateDefaultTimeout end def check_arity(req_args, num_args) if ((req_args > 0 and num_args != req_args) || (req_args < 0 and num_args < req_args.abs)) xputs "[ERR] Wrong number of arguments for specified sub command" exit 1 end end def add_node(node) @nodes << node end def reset_nodes @nodes = [] end def cluster_error(msg) @errors << msg xputs msg end # Return the node with the specified ID or Nil. def get_node_by_name(name) @nodes.each{|n| return n if n.info[:name] == name.downcase } return nil end # Like get_node_by_name but the specified name can be just the first # part of the node ID as long as the prefix in unique across the # cluster. def get_node_by_abbreviated_name(name) l = name.length candidates = [] @nodes.each{|n| if n.info[:name][0...l] == name.downcase candidates << n end } return nil if candidates.length != 1 candidates[0] end # This function returns the master that has the least number of replicas # in the cluster. If there are multiple masters with the same smaller # number of replicas, one at random is returned. def get_master_with_least_replicas masters = @nodes.select{|n| n.has_flag? "master"} sorted = masters.sort{|a,b| a.info[:replicas].length <=> b.info[:replicas].length } sorted[0] end def check_cluster(opt={}) xputs ">>> Performing Cluster Check (using node #{@nodes[0]})" show_nodes if !opt[:quiet] check_config_consistency check_open_slots check_slots_coverage end def show_cluster_info masters = 0 keys = 0 @nodes.each{|n| if n.has_flag?("master") puts "#{n} (#{n.info[:name][0...8]}...) -> #{n.r.dbsize} keys | #{n.slots.length} slots | "+ "#{n.info[:replicas].length} slaves." masters += 1 keys += n.r.dbsize end } xputs "[OK] #{keys} keys in #{masters} masters." keys_per_slot = sprintf("%.2f",keys/16384.0) puts "#{keys_per_slot} keys per slot on average." end # Merge slots of every known node. If the resulting slots are equal # to ClusterHashSlots, then all slots are served. def covered_slots slots = {} @nodes.each{|n| slots = slots.merge(n.slots) } slots end def check_slots_coverage xputs ">>> Check slots coverage..." slots = covered_slots if slots.length == ClusterHashSlots xputs "[OK] All #{ClusterHashSlots} slots covered." else cluster_error \ "[ERR] Not all #{ClusterHashSlots} slots are covered by nodes." fix_slots_coverage if @fix end end def check_open_slots xputs ">>> Check for open slots..." open_slots = [] @nodes.each{|n| if n.info[:migrating].size > 0 cluster_error \ "[WARNING] Node #{n} has slots in migrating state (#{n.info[:migrating].keys.join(",")})." open_slots += n.info[:migrating].keys end if n.info[:importing].size > 0 cluster_error \ "[WARNING] Node #{n} has slots in importing state (#{n.info[:importing].keys.join(",")})." open_slots += n.info[:importing].keys end } open_slots.uniq! if open_slots.length > 0 xputs "[WARNING] The following slots are open: #{open_slots.join(",")}" end if @fix open_slots.each{|slot| fix_open_slot slot} end end def nodes_with_keys_in_slot(slot) nodes = [] @nodes.each{|n| next if n.has_flag?("slave") nodes << n if n.r.cluster("getkeysinslot",slot,1).length > 0 } nodes end def fix_slots_coverage not_covered = (0...ClusterHashSlots).to_a - covered_slots.keys xputs ">>> Fixing slots coverage..." xputs "List of not covered slots: " + not_covered.join(",") # For every slot, take action depending on the actual condition: # 1) No node has keys for this slot. # 2) A single node has keys for this slot. # 3) Multiple nodes have keys for this slot. slots = {} not_covered.each{|slot| nodes = nodes_with_keys_in_slot(slot) slots[slot] = nodes xputs "Slot #{slot} has keys in #{nodes.length} nodes: #{nodes.join(", ")}" } none = slots.select {|k,v| v.length == 0} single = slots.select {|k,v| v.length == 1} multi = slots.select {|k,v| v.length > 1} # Handle case "1": keys in no node. if none.length > 0 xputs "The folowing uncovered slots have no keys across the cluster:" xputs none.keys.join(",") yes_or_die "Fix these slots by covering with a random node?" none.each{|slot,nodes| node = @nodes.sample xputs ">>> Covering slot #{slot} with #{node}" node.r.cluster("addslots",slot) } end # Handle case "2": keys only in one node. if single.length > 0 xputs "The folowing uncovered slots have keys in just one node:" puts single.keys.join(",") yes_or_die "Fix these slots by covering with those nodes?" single.each{|slot,nodes| xputs ">>> Covering slot #{slot} with #{nodes[0]}" nodes[0].r.cluster("addslots",slot) } end # Handle case "3": keys in multiple nodes. if multi.length > 0 xputs "The folowing uncovered slots have keys in multiple nodes:" xputs multi.keys.join(",") yes_or_die "Fix these slots by moving keys into a single node?" multi.each{|slot,nodes| target = get_node_with_most_keys_in_slot(nodes,slot) xputs ">>> Covering slot #{slot} moving keys to #{target}" target.r.cluster('addslots',slot) target.r.cluster('setslot',slot,'stable') nodes.each{|src| next if src == target # Set the source node in 'importing' state (even if we will # actually migrate keys away) in order to avoid receiving # redirections for MIGRATE. src.r.cluster('setslot',slot,'importing',target.info[:name]) move_slot(src,target,slot,:dots=>true,:fix=>true,:cold=>true) src.r.cluster('setslot',slot,'stable') } } end end # Return the owner of the specified slot def get_slot_owners(slot) owners = [] @nodes.each{|n| next if n.has_flag?("slave") n.slots.each{|s,_| owners << n if s == slot } } owners end # Return the node, among 'nodes' with the greatest number of keys # in the specified slot. def get_node_with_most_keys_in_slot(nodes,slot) best = nil best_numkeys = 0 @nodes.each{|n| next if n.has_flag?("slave") numkeys = n.r.cluster("countkeysinslot",slot) if numkeys > best_numkeys || best == nil best = n best_numkeys = numkeys end } return best end # Slot 'slot' was found to be in importing or migrating state in one or # more nodes. This function fixes this condition by migrating keys where # it seems more sensible. def fix_open_slot(slot) puts ">>> Fixing open slot #{slot}" # Try to obtain the current slot owner, according to the current # nodes configuration. owners = get_slot_owners(slot) owner = owners[0] if owners.length == 1 migrating = [] importing = [] @nodes.each{|n| next if n.has_flag? "slave" if n.info[:migrating][slot] migrating << n elsif n.info[:importing][slot] importing << n elsif n.r.cluster("countkeysinslot",slot) > 0 && n != owner xputs "*** Found keys about slot #{slot} in node #{n}!" importing << n end } puts "Set as migrating in: #{migrating.join(",")}" puts "Set as importing in: #{importing.join(",")}" # If there is no slot owner, set as owner the slot with the biggest # number of keys, among the set of migrating / importing nodes. if !owner xputs ">>> Nobody claims ownership, selecting an owner..." owner = get_node_with_most_keys_in_slot(@nodes,slot) # If we still don't have an owner, we can't fix it. if !owner xputs "[ERR] Can't select a slot owner. Impossible to fix." exit 1 end # Use ADDSLOTS to assign the slot. puts "*** Configuring #{owner} as the slot owner" owner.r.cluster("setslot",slot,"stable") owner.r.cluster("addslots",slot) # Make sure this information will propagate. Not strictly needed # since there is no past owner, so all the other nodes will accept # whatever epoch this node will claim the slot with. owner.r.cluster("bumpepoch") # Remove the owner from the list of migrating/importing # nodes. migrating.delete(owner) importing.delete(owner) end # If there are multiple owners of the slot, we need to fix it # so that a single node is the owner and all the other nodes # are in importing state. Later the fix can be handled by one # of the base cases above. # # Note that this case also covers multiple nodes having the slot # in migrating state, since migrating is a valid state only for # slot owners. if owners.length > 1 owner = get_node_with_most_keys_in_slot(owners,slot) owners.each{|n| next if n == owner n.r.cluster('delslots',slot) n.r.cluster('setslot',slot,'importing',owner.info[:name]) importing.delete(n) # Avoid duplciates importing << n } owner.r.cluster('bumpepoch') end # Case 1: The slot is in migrating state in one slot, and in # importing state in 1 slot. That's trivial to address. if migrating.length == 1 && importing.length == 1 move_slot(migrating[0],importing[0],slot,:dots=>true,:fix=>true) # Case 2: There are multiple nodes that claim the slot as importing, # they probably got keys about the slot after a restart so opened # the slot. In this case we just move all the keys to the owner # according to the configuration. elsif migrating.length == 0 && importing.length > 0 xputs ">>> Moving all the #{slot} slot keys to its owner #{owner}" importing.each {|node| next if node == owner move_slot(node,owner,slot,:dots=>true,:fix=>true,:cold=>true) xputs ">>> Setting #{slot} as STABLE in #{node}" node.r.cluster("setslot",slot,"stable") } # Case 3: There are no slots claiming to be in importing state, but # there is a migrating node that actually don't have any key. We # can just close the slot, probably a reshard interrupted in the middle. elsif importing.length == 0 && migrating.length == 1 && migrating[0].r.cluster("getkeysinslot",slot,10).length == 0 migrating[0].r.cluster("setslot",slot,"stable") else xputs "[ERR] Sorry, Redis-trib can't fix this slot yet (work in progress). Slot is set as migrating in #{migrating.join(",")}, as importing in #{importing.join(",")}, owner is #{owner}" end end # Check if all the nodes agree about the cluster configuration def check_config_consistency if !is_config_consistent? cluster_error "[ERR] Nodes don't agree about configuration!" else xputs "[OK] All nodes agree about slots configuration." end end def is_config_consistent? signatures=[] @nodes.each{|n| signatures << n.get_config_signature } return signatures.uniq.length == 1 end def wait_cluster_join print "Waiting for the cluster to join" while !is_config_consistent? print "." STDOUT.flush sleep 1 end print "\n" end def alloc_slots nodes_count = @nodes.length masters_count = @nodes.length / (@replicas+1) masters = [] # The first step is to split instances by IP. This is useful as # we'll try to allocate master nodes in different physical machines # (as much as possible) and to allocate slaves of a given master in # different physical machines as well. # # This code assumes just that if the IP is different, than it is more # likely that the instance is running in a different physical host # or at least a different virtual machine. ips = {} @nodes.each{|n| ips[n.info[:host]] = [] if !ips[n.info[:host]] ips[n.info[:host]] << n } # Select master instances puts "Using #{masters_count} masters:" interleaved = [] stop = false while not stop do # Take one node from each IP until we run out of nodes # across every IP. ips.each do |ip,nodes| if nodes.empty? # if this IP has no remaining nodes, check for termination if interleaved.length == nodes_count # stop when 'interleaved' has accumulated all nodes stop = true next end else # else, move one node from this IP to 'interleaved' interleaved.push nodes.shift end end end masters = interleaved.slice!(0, masters_count) nodes_count -= masters.length masters.each{|m| puts m} # Alloc slots on masters slots_per_node = ClusterHashSlots.to_f / masters_count first = 0 cursor = 0.0 masters.each_with_index{|n,masternum| last = (cursor+slots_per_node-1).round if last > ClusterHashSlots || masternum == masters.length-1 last = ClusterHashSlots-1 end last = first if last < first # Min step is 1. n.add_slots first..last first = last+1 cursor += slots_per_node } # Select N replicas for every master. # We try to split the replicas among all the IPs with spare nodes # trying to avoid the host where the master is running, if possible. # # Note we loop two times. The first loop assigns the requested # number of replicas to each master. The second loop assigns any # remaining instances as extra replicas to masters. Some masters # may end up with more than their requested number of replicas, but # all nodes will be used. assignment_verbose = false [:requested,:unused].each do |assign| masters.each do |m| assigned_replicas = 0 while assigned_replicas < @replicas break if nodes_count == 0 if assignment_verbose if assign == :requested puts "Requesting total of #{@replicas} replicas " \ "(#{assigned_replicas} replicas assigned " \ "so far with #{nodes_count} total remaining)." elsif assign == :unused puts "Assigning extra instance to replication " \ "role too (#{nodes_count} remaining)." end end # Return the first node not matching our current master node = interleaved.find{|n| n.info[:host] != m.info[:host]} # If we found a node, use it as a best-first match. # Otherwise, we didn't find a node on a different IP, so we # go ahead and use a same-IP replica. if node slave = node interleaved.delete node else slave = interleaved.shift end slave.set_as_replica(m.info[:name]) nodes_count -= 1 assigned_replicas += 1 puts "Adding replica #{slave} to #{m}" # If we are in the "assign extra nodes" loop, # we want to assign one extra replica to each # master before repeating masters. # This break lets us assign extra replicas to masters # in a round-robin way. break if assign == :unused end end end end def flush_nodes_config @nodes.each{|n| n.flush_node_config } end def show_nodes @nodes.each{|n| xputs n.info_string } end # Redis Cluster config epoch collision resolution code is able to eventually # set a different epoch to each node after a new cluster is created, but # it is slow compared to assign a progressive config epoch to each node # before joining the cluster. However we do just a best-effort try here # since if we fail is not a problem. def assign_config_epoch config_epoch = 1 @nodes.each{|n| begin n.r.cluster("set-config-epoch",config_epoch) rescue end config_epoch += 1 } end def join_cluster # We use a brute force approach to make sure the node will meet # each other, that is, sending CLUSTER MEET messages to all the nodes # about the very same node. # Thanks to gossip this information should propagate across all the # cluster in a matter of seconds. first = false @nodes.each{|n| if !first then first = n.info; next; end # Skip the first node n.r.cluster("meet",first[:host],first[:port]) } end def yes_or_die(msg) print "#{msg} (type 'yes' to accept): " STDOUT.flush if !(STDIN.gets.chomp.downcase == "yes") xputs "*** Aborting..." exit 1 end end def load_cluster_info_from_node(nodeaddr) node = ClusterNode.new(nodeaddr) node.connect(:abort => true) node.assert_cluster node.load_info(:getfriends => true) add_node(node) node.friends.each{|f| next if f[:flags].index("noaddr") || f[:flags].index("disconnected") || f[:flags].index("fail") fnode = ClusterNode.new(f[:addr]) fnode.connect() next if !fnode.r begin fnode.load_info() add_node(fnode) rescue => e xputs "[ERR] Unable to load info for node #{fnode}" end } populate_nodes_replicas_info end # This function is called by load_cluster_info_from_node in order to # add additional information to every node as a list of replicas. def populate_nodes_replicas_info # Start adding the new field to every node. @nodes.each{|n| n.info[:replicas] = [] } # Populate the replicas field using the replicate field of slave # nodes. @nodes.each{|n| if n.info[:replicate] master = get_node_by_name(n.info[:replicate]) if !master xputs "*** WARNING: #{n} claims to be slave of unknown node ID #{n.info[:replicate]}." else master.info[:replicas] << n end end } end # Given a list of source nodes return a "resharding plan" # with what slots to move in order to move "numslots" slots to another # instance. def compute_reshard_table(sources,numslots) moved = [] # Sort from bigger to smaller instance, for two reasons: # 1) If we take less slots than instances it is better to start # getting from the biggest instances. # 2) We take one slot more from the first instance in the case of not # perfect divisibility. Like we have 3 nodes and need to get 10 # slots, we take 4 from the first, and 3 from the rest. So the # biggest is always the first. sources = sources.sort{|a,b| b.slots.length <=> a.slots.length} source_tot_slots = sources.inject(0) {|sum,source| sum+source.slots.length } sources.each_with_index{|s,i| # Every node will provide a number of slots proportional to the # slots it has assigned. n = (numslots.to_f/source_tot_slots*s.slots.length) if i == 0 n = n.ceil else n = n.floor end s.slots.keys.sort[(0...n)].each{|slot| if moved.length < numslots moved << {:source => s, :slot => slot} end } } return moved end def show_reshard_table(table) table.each{|e| puts " Moving slot #{e[:slot]} from #{e[:source].info[:name]}" } end # Move slots between source and target nodes using MIGRATE. # # Options: # :verbose -- Print a dot for every moved key. # :fix -- We are moving in the context of a fix. Use REPLACE. # :cold -- Move keys without opening slots / reconfiguring the nodes. # :update -- Update nodes.info[:slots] for source/target nodes. # :quiet -- Don't print info messages. def move_slot(source,target,slot,o={}) o = {:pipeline => MigrateDefaultPipeline}.merge(o) # We start marking the slot as importing in the destination node, # and the slot as migrating in the target host. Note that the order of # the operations is important, as otherwise a client may be redirected # to the target node that does not yet know it is importing this slot. if !o[:quiet] print "Moving slot #{slot} from #{source} to #{target}: " STDOUT.flush end if !o[:cold] target.r.cluster("setslot",slot,"importing",source.info[:name]) source.r.cluster("setslot",slot,"migrating",target.info[:name]) end # Migrate all the keys from source to target using the MIGRATE command while true keys = source.r.cluster("getkeysinslot",slot,o[:pipeline]) break if keys.length == 0 begin source.r.client.call(["migrate",target.info[:host],target.info[:port],"",0,@timeout,:keys,*keys]) rescue => e if o[:fix] && e.to_s =~ /BUSYKEY/ xputs "*** Target key exists. Replacing it for FIX." source.r.client.call(["migrate",target.info[:host],target.info[:port],"",0,@timeout,:replace,:keys,*keys]) else puts "" xputs "[ERR] Calling MIGRATE: #{e}" exit 1 end end print "."*keys.length if o[:dots] STDOUT.flush end puts if !o[:quiet] # Set the new node as the owner of the slot in all the known nodes. if !o[:cold] @nodes.each{|n| next if n.has_flag?("slave") n.r.cluster("setslot",slot,"node",target.info[:name]) } end # Update the node logical config if o[:update] then source.info[:slots].delete(slot) target.info[:slots][slot] = true end end # redis-trib subcommands implementations. def check_cluster_cmd(argv,opt) load_cluster_info_from_node(argv[0]) check_cluster end def info_cluster_cmd(argv,opt) load_cluster_info_from_node(argv[0]) show_cluster_info end def rebalance_cluster_cmd(argv,opt) opt = { 'pipeline' => MigrateDefaultPipeline, 'threshold' => RebalanceDefaultThreshold }.merge(opt) # Load nodes info before parsing options, otherwise we can't # handle --weight. load_cluster_info_from_node(argv[0]) # Options parsing threshold = opt['threshold'].to_i autoweights = opt['auto-weights'] weights = {} opt['weight'].each{|w| fields = w.split("=") node = get_node_by_abbreviated_name(fields[0]) if !node || !node.has_flag?("master") puts "*** No such master node #{fields[0]}" exit 1 end weights[node.info[:name]] = fields[1].to_f } if opt['weight'] useempty = opt['use-empty-masters'] # Assign a weight to each node, and compute the total cluster weight. total_weight = 0 nodes_involved = 0 @nodes.each{|n| if n.has_flag?("master") next if !useempty && n.slots.length == 0 n.info[:w] = weights[n.info[:name]] ? weights[n.info[:name]] : 1 total_weight += n.info[:w] nodes_involved += 1 end } # Check cluster, only proceed if it looks sane. check_cluster(:quiet => true) if @errors.length != 0 puts "*** Please fix your cluster problems before rebalancing" exit 1 end # Calculate the slots balance for each node. It's the number of # slots the node should lose (if positive) or gain (if negative) # in order to be balanced. threshold = opt['threshold'].to_f threshold_reached = false @nodes.each{|n| if n.has_flag?("master") next if !n.info[:w] expected = ((ClusterHashSlots.to_f / total_weight) * n.info[:w]).to_i n.info[:balance] = n.slots.length - expected # Compute the percentage of difference between the # expected number of slots and the real one, to see # if it's over the threshold specified by the user. over_threshold = false if threshold > 0 if n.slots.length > 0 err_perc = (100-(100.0*expected/n.slots.length)).abs over_threshold = true if err_perc > threshold elsif expected > 0 over_threshold = true end end threshold_reached = true if over_threshold end } if !threshold_reached xputs "*** No rebalancing needed! All nodes are within the #{threshold}% threshold." return end # Only consider nodes we want to change sn = @nodes.select{|n| n.has_flag?("master") && n.info[:w] } # Because of rounding, it is possible that the balance of all nodes # summed does not give 0. Make sure that nodes that have to provide # slots are always matched by nodes receiving slots. total_balance = sn.map{|x| x.info[:balance]}.reduce{|a,b| a+b} while total_balance > 0 sn.each{|n| if n.info[:balance] < 0 && total_balance > 0 n.info[:balance] -= 1 total_balance -= 1 end } end # Sort nodes by their slots balance. sn = sn.sort{|a,b| a.info[:balance] <=> b.info[:balance] } xputs ">>> Rebalancing across #{nodes_involved} nodes. Total weight = #{total_weight}" if $verbose sn.each{|n| puts "#{n} balance is #{n.info[:balance]} slots" } end # Now we have at the start of the 'sn' array nodes that should get # slots, at the end nodes that must give slots. # We take two indexes, one at the start, and one at the end, # incrementing or decrementing the indexes accordingly til we # find nodes that need to get/provide slots. dst_idx = 0 src_idx = sn.length - 1 while dst_idx < src_idx dst = sn[dst_idx] src = sn[src_idx] numslots = [dst.info[:balance],src.info[:balance]].map{|n| n.abs }.min if numslots > 0 puts "Moving #{numslots} slots from #{src} to #{dst}" # Actaully move the slots. reshard_table = compute_reshard_table([src],numslots) if reshard_table.length != numslots xputs "*** Assertio failed: Reshard table != number of slots" exit 1 end if opt['simulate'] print "#"*reshard_table.length else reshard_table.each{|e| move_slot(e[:source],dst,e[:slot], :quiet=>true, :dots=>false, :update=>true, :pipeline=>opt['pipeline']) print "#" STDOUT.flush } end puts end # Update nodes balance. dst.info[:balance] += numslots src.info[:balance] -= numslots dst_idx += 1 if dst.info[:balance] == 0 src_idx -= 1 if src.info[:balance] == 0 end end def fix_cluster_cmd(argv,opt) @fix = true @timeout = opt['timeout'].to_i if opt['timeout'] load_cluster_info_from_node(argv[0]) check_cluster end def reshard_cluster_cmd(argv,opt) opt = {'pipeline' => MigrateDefaultPipeline}.merge(opt) load_cluster_info_from_node(argv[0]) check_cluster if @errors.length != 0 puts "*** Please fix your cluster problems before resharding" exit 1 end @timeout = opt['timeout'].to_i if opt['timeout'].to_i # Get number of slots if opt['slots'] numslots = opt['slots'].to_i else numslots = 0 while numslots <= 0 or numslots > ClusterHashSlots print "How many slots do you want to move (from 1 to #{ClusterHashSlots})? " numslots = STDIN.gets.to_i end end # Get the target instance if opt['to'] target = get_node_by_name(opt['to']) if !target || target.has_flag?("slave") xputs "*** The specified node is not known or not a